What does "al dente" mean when cooking pasta?

Ask any Italian how pasta should be cooked and you’ll receive the same response: al dente. Literally translated as "to the tooth," al dente is an Italian term used to describe the ideal consistency of pasta (and rice) when cooked. Al dente pasta is firm when bitten without being hard or chalky. Italians call pasta that has been cooked until soft "stracotto" (overcooked).

Source: Pasta Evangelists